[kube] use local image for kubernetes integration tests

.github/workflows/kube-integration-tests-non-root.yaml

@@ -92,11 +92,6 @@ jobs:
 
       - name: Build Alpine image with webserver
         run: |
-          # download alpine minirootfs and signature
-          curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz
-          curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.asc https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.asc
-          curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.sha256 https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.sha256
-
           # verify the checksum
           cd ./fixtures/alpine/ && sha256sum -c alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.sha256 && cd -
 

.gitignore

@@ -12,6 +12,8 @@ default.etcd
 
 # usually release tarballs get in the way
 *.gz
+# ignore all tarballs except the alpine one
+!fixtures/alpine/alpine-minirootfs-*.tar.gz
 *.zip
 
 # editors

fixtures/alpine/README.md

@@ -6,7 +6,26 @@ The `alpine-webserver:v1` image is based on `alpine` `minirootfs`, but instead o
 
 The build process is specified in the `.github/workflows/kube-integration-tests-non-root.yaml` file.
 
-To avoid distributing Alpine Linux within the Teleport repository, we download it fresh from the Alpine CDN with each build. The download includes the minirootfs (3.3MB), along with the corresponding SHA-256 checksum and GPG signature files for verification.
+## Download
+
+To download the new `alpine-minirootfs` image, follow the instructions:
+
+Define the desired Alpine version:
+
+```bash
+$ export ALPINE_VERSION=3.20.3
+```
+
+Download the asset files: filesystem, signature and sha256.
+
+```bash
+
+# download alpine minirootfs and signature
+$ curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz
+$ curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.asc https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.asc
+$ curl -fSsL -o ./fixtures/alpine/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.sha256 https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-minirootfs-$ALPINE_VERSION-x86_64.tar.gz.sha256
+
+```
 
 ## Source Validation
 

fixtures/alpine/alpine-minirootfs-3.20.3-x86_64.tar.gz.asc

@@ -0,0 +1,16 @@
+-----BEGIN PGP SIGNATURE-----
+
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+EA0SA8Tam8QNaBZHBWQxgmEw2iqfZPxIAqc188GzXeO8GWGjXILR2t4wOEEEmRa3
+g8REzQ8xpVOs/6y2woolNZWYFi5lCc1Do+KxRbdyEP3P1scz5D2FYfA8I6i/iwk9
+TR155MItfdB7nPDTvkR6p0xpI5H1V6sSKKk2EricwyvTKVoTBYa19h8pIA7fOzqQ
+h32qlxW0Xfn96VZUvlsxCuPlJT8nAkxE1uotmJPb5NIuLo2SLgTB4eHKhvnryi0c
+WYtrogEC5rCF+btCU3/7DcMd7BJnPW3otUQL/+iAxWlCQ4YoKx9qltC1O8qres5p
+9hbF7Wv88aEuqfoi1JZDaAACeITAKLEMWaiT9pCXLJ0EeghE2y5yfC7kTh4+faS6
++cGoY1+Zmvp6o0ENG+GURkn7jx6WJ3MC9zaEgmfYbovPov4iBLg=
+=+T7J
+-----END PGP SIGNATURE-----

fixtures/alpine/alpine-minirootfs-3.20.3-x86_64.tar.gz.sha256

@@ -0,0 +1 @@
+d4e6fd67dcf75e40c451560ac7265166c2b72a0f38ddc9aae756a7de3d1efa0c  alpine-minirootfs-3.20.3-x86_64.tar.gz